Dual cure polythioether

ABSTRACT

Compositions that are curable to polythioether polymers are provided, comprising: a) a dithiol monomer; b) a diene monomer; c) a radical cleaved photoinitiator; d) a peroxide; and e) an amine; where the peroxide and amine together are a peroxide-amine redox initiator. In some embodiments, the amine is a tertiary amine. In some embodiments, the amine is selected from the group consisting of dihydroxyethyl-p-toluidine, N,N-diisopropylethylamine, and N, N, N′, N″, N″-pentamethyl-diethylenetriamine. In some embodiments, the peroxide is selected from the group consisting of di-tert-butyl peroxide, methyl ethyl ketone peroxide, and benzoyl peroxide. In some embodiments, the composition may additionally comprise a polythiol monomer having three or more thiol groups.

FIELD OF THE DISCLOSURE

This disclosure relates to compositions that cure to form polythioetherpolymers and that include a dual cure curing mechanism, as well assealants comprising the same.

SUMMARY OF THE DISCLOSURE

Briefly, the present disclosure provides compositions that are curableto polythioether polymers, comprising: a) a dithiol monomer; b) a dienemonomer; c) a radical cleaved photoinitiator; d) a peroxide; and e) anamine; where the peroxide and amine together are a peroxide-amine redoxinitiator. In some embodiments, the amine is a tertiary amine. In someembodiments, the amine is selected from the group consisting ofdihydroxyethyl-p-toluidine, N,N-diisopropylethylamine, and N, N, N′, N″,N″-pentamethyl-diethylenetriamine. In some embodiments, the peroxide isselected from the group consisting of di-tert-butyl peroxide, methylethyl ketone peroxide, and benzoyl peroxide. In some embodiments, thecomposition may additionally comprise a polythiol monomer having threeor more thiol groups. In some embodiments, the composition mayadditionally comprise one or more fillers. In some embodiments, thecomposition may additionally comprise one or more nanoparticle fillers.In some embodiments, the composition may additionally comprise calciumcarbonate. In some embodiments, the composition may additionallycomprise nanoparticle calcium carbonate. In some embodiments, thecomposition may be cured by application of light from an actinic lightsource. In some embodiments, the composition may be cured by applicationof light from a blue light source. In some embodiments, the compositionmay be cured by application of light from a UV light source.

In another aspect, the present disclosure provides sealants comprisingcurable compositions according to the present disclosure. In anotheraspect, the present disclosure provides seals obtained by cure of suchsealants.

In another aspect, the present disclosure provides polythioetherpolymers obtained by cure of any the compositions according to thepresent disclosure. In some embodiments, the polythioether polymer has aTg less than −50° C. In some embodiments, the polythioether polymerexhibits high jet fuel resistance characterized by a volume swell ofless than 30% and a weight gain of less than 20% when measured accordingto Society of Automotive Engineers (SAE) International StandardAS5127/1.

All scientific and technical terms used herein have meanings commonlyused in the art unless otherwise specified.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” encompass embodiments having pluralreferents, unless the content clearly dictates otherwise.

As used in this specification and the appended claims, the term “or” isgenerally employed in its sense including “and/or” unless the contentclearly dictates otherwise.

As used herein, “have”, “having”, “include”, “including”, “comprise”,“comprising” or the like are used in their open ended sense, andgenerally mean “including, but not limited to.” It will be understoodthat the terms “consisting of” and “consisting essentially of” aresubsumed in the term “comprising,” and the like.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a diagram representing the use of a dual cure polythioetheraccording the the present invention as a sealant between two substrates.

DETAILED DESCRIPTION

The present disclosure provides a dual cure polythioether material suchas a sealant. In some embodiments the sealant has both cure on demandproperties and dark cure properties. In some embodiments the sealant maybe cured by exposure to actinic radiation in 120 seconds or less, insome embodiments 90 seconds or less, in some embodiments 60 seconds orless, in some embodiments 30 seconds or less, and in some embodiments 20seconds or less. In some embodiments cure on demand can be initiatedwith UV light, in some with visible light, in some with LED sourced UVlight, and in some with LED sourced visible light. Furthermore, in someembodiments the initially photoinitiated cure propagates by a dark curemechanism into adjacent portions of the polythioether material that arewithout light access. In some embodiments cure propagates by at least2.5 cm into the dark zone with 90% or greater conversion in 120 secondsor less, in some embodiments 90 seconds or less, in some embodiments 60seconds or less, in some embodiments 30 seconds or less, and in someembodiments 20 seconds or less. In some embodiments cure propagates byat least 5.0 cm into the dark zone with 90% or greater conversion in 120seconds or less, in some embodiments 90 seconds or less, in someembodiments 60 seconds or less, in some embodiments 30 seconds or less,and in some embodiments 20 seconds or less.

With reference to FIG. 1, in one embodiment of a sealant according tothe present disclosure, sealant 10 is applied between opaque substrates20. Actinic light 40 from actinic light source 30 is used to initiatecure of a portion of sealant 10 exposed to said light, in exposed zone100. However, sealant 10 in dark zones 110 and 120 is not exposed toactinic light 40. Use of the dual cure initiation system of the presentdisclosure allows the initially photoinitiated cure to propagate by adark cure mechanism into adjacent dark zones 110 and 120. In someembodiments, sealant in dark zone 110, representing the 2 inches (5 cm)immediately adjacent to exposed zone 100, is fully cured within 20seconds, and cure continues further into dark zone 120.

In some embodiments, the initiation system includes a) a radical cleavedphotoinitiator and b) a peroxide-amine redox initiator.

In some embodiments, the cured material has low glass transitiontemperature, in some embodiments less than −20° C., in some embodimentsless than −30° C., in some embodiments less than −40° C., and in someembodiments less than −50° C. In some embodiments, the cured materialhas excellent fuel resistance properties. In some embodiments, the curedmaterial combines low glass transition temperature of less than −50° C.with excellent fuel resistance properties. Thus, in certain embodimentsthis dual cure technology can be applied to aircraft or automobilesealant applications and may result in greater ease and speed of vehiclemanufacture.

Selected Embodiments

The following numbered embodiments are intended to further illustratethe present disclosure but should not be construed to unduly limit thisdisclosure.

1. A composition that is curable to a polythioether polymer, comprising:

a) a dithiol monomer;

b) a diene monomer;

c) a radical cleaved photoinitiator;

d) a peroxide; and

e) an amine;

where the peroxide and amine together are a peroxide-amine redoxinitiator.2. The composition according to embodiment 1 where the amine is atertiary amine.3. The composition according to any of the preceding embodiments wherethe amine is selected from the group consisting ofdihydroxyethyl-p-toluidine, N,N-diisopropylethylamine, and N, N, N′, N″,N″-pentamethyl-diethylenetriamine.4. The composition according to any of the preceding embodiments wherethe peroxide is selected from the group consisting of di-tert-butylperoxide, methyl ethyl ketone peroxide, and benzoyl peroxide.5. The composition according to any of the preceding embodimentsadditionally comprising:

f) a polythiol monomer having three or more thiol groups.

6. The composition according to any of the preceding embodimentsadditionally comprising:

g) at least one filler.

7. The composition according to any of the preceding embodimentsadditionally comprising:

h) at least one nanoparticle filler.

8. The composition according to any of the preceding embodimentsadditionally comprising:

j) calcium carbonate.

9. The composition according to any of the preceding embodimentsadditionally comprising:

k) nanoparticle calcium carbonate.

10. The composition according to any of the preceding embodiments whichis curable by actinic light source.11. The composition according to any of the preceding embodiments whichis curable by blue light source.12. The composition according to any of the preceding embodiments whichis curable by UV light source.13. A sealant comprising the composition according to any of thepreceding embodiments.14. A polythioether polymer obtained by cure of any the compositionaccording to any of embodiments 1-12.15. The polythioether polymer according to embodiment 14 having a Tgless than −50° C.16. The polythioether polymer according to embodiment 14 or 15 whichexhibits high jet fuel resistence characterized by a volume swell ofless than 30% and a weight gain of less than 20% when measured accordingto Society of Automotive Engineers (SAE) International StandardAS5127/1.

Objects and advantages of this disclosure are further illustrated by thefollowing examples, but the particular materials and amounts thereofrecited in these examples, as well as other conditions and details,should not be construed to unduly limit this disclosure.

EXAMPLES

Unless otherwise noted, all reagents were obtained or are available fromSigma-Aldrich Company, St. Louis, Mo., or may be synthesized by knownmethods.

Unless otherwise reported, all ratios are by weight percent.

The following abbreviations are used to describe the examples:

° C.: degrees Centigrade

cm: centimeter

LED: light emitting diode

mL: milliliter

Mn: Molecular weight

mW: milliWatt

nm: nanometer

T_(g): glass transition temperature

UV: ultraviolet

Definitions

Maximum Processing Time: The time taken for the thiol-ene curablecomposition to begin gelling.

Photo Cure Time: The cure time of the portion of thiol-ene curablecomposition exposed to light.

Dark Cure Time: The cure time of the portion of thiol-ene curablecomposition not exposed to light.

Redox Cure Time: The cure time for the portion of thiol-ene curablecomposition initiated by redox mechanism.

Dark Cure Distance: The length of thiol-ene composition dark cured, asmeasured from the leading edge of the opaque silicone rubber sheet.

Materials.

Abbreviations for the materials used in the examples are as follows:

-   A-200: A hydrophilic fumed silica, obtained under the trade    designation “AEROSIL 200” from Evonik Industries AG, Essen, Germany.-   BPO: Benzoyl peroxide.-   CMP: 3-chloro-2-methyl-1-propene.-   DABCO: 1,4-Diazabicyclo[2.2.2]octane, obtained under the trade    designation-   “DABCO” from Air Products & Chemicals, Inc., Allentown, Pa.-   DHEPT: dihydroxyethyl-p-toluidine.-   DIPEA: N,N-diisopropylethylamine, obtained from Alfa Aesar, Ward    Hill, Mass.-   DMDO: 1,8-Dimercapto-3,6-dioxaoctane, obtained from Arkena, Inc.,    King of Prussia, Pa.-   DSW: An aluminosilicate clay, obtained under the trade designation-   “DRAGONITE SELECT WHITE” from Applied Minerals, Inc., New York, N.Y.-   DVE-3: Triethyleneglycol divinylether, obtained under the trade    designation “RAPI-CURE DVE-3” from Ashland Specialty Ingredients,    Wilmington, Del.-   E-8220: A diglycidylether of bisphenol F, obtained under the trade    designation “EPALLOY 8220” from Emerald Performance Materials, LLC,    Cuyahoga Falls, Ohio.-   I-819: Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, obtained    under the trade designation “IRGACURE 819” from BASF Corp., Florham    Park, N.J.-   MEHQ: Hydroquinone monomethyl ether.-   MEKP: Methyl ethyl ketone peroxide, obtained from 3M Company, St.    Paul, Minn.-   PMETA: N, N, N′, N″, N″-pentamethyl-diethylenetriamine, obtained    from TCI America, Portland, Oreg.-   S-31: Nanoparticle (70-100 nm) calcium carbonate, obtained under the    trade designation “SOCAL 31” from Solvay Chemicals, Inc., Houston,    Tex.-   TAC: Triallylcyanurate, obtained from Sartomer, Inc., Exton, Pa.-   TBPO: di-tert-butyl peroxide, obtained from TCI America.-   TEMPO: 2,2,6,6-tetramethyl-1-piperidinyloxy, obtained from Oakwood    Products, Inc., West Columbia, S.C.-   TPTMP: Trimethylolpropane tris(3-mercaptopropionate).-   TVCH: 1,2,4-Trivinylcyclohexane, obtained from BASF Corp., Florham    Park, N.J.-   TVBT: tris[4-(vinyloxy)butyl] trimellitate, obtained from Allied    Signal, Inc., Morristown, N.J.-   VAZO 52: 2,2′-azobis(2,4-dimethyl-pentanenitrile), obtained under    the trade designation “VAZO 52” from E.I. du Dupont de Nemours and    Company, Wilmington, Del.-   VAZO 67: 2,2′azobis-(2-methylbutyronitrile), obtained under the    trade designation “VAZO 67” from E.I. du Dupont de Nemours and    Company.    Polythioethers were Synthesized as Follows:

PTE-1. Into a 1000-mL round bottom flask equipped with an air-drivenstirrer, thermometer, and a dropping funnel, was added 392.14 grams(2.15 moles) DMDO and 82.23 grams (0.25 moles) E-8220. To this mixturewas added 0.15 grams DABCO. The system was flushed with nitrogen, thenmixed and heated for four hours at 60-70° C. 12.5 grams (0.05 moles) TACwas added, followed by approximately 0.15 grams VAZO 67. With continuousstirring, the mixture was heated to 60° C., and held at this temperaturefor approximately 30-45 minutes. 313.13 grams (1.55 moles) DVE-3 wereslowly added drop-wise to the flask over a period of 45-60 minutes,keeping the temperature at approximately between 68-80° C. AdditionalVAZO 67 was added in approximately 0.15 gram increments overapproximately 6 hours, for a total of approximately 0.6 grams. Thetemperature was raised to 100° C. and the material degassed forapproximately 10 minutes. The resultant polythioether was approximately3200 Mn with a 2.2 functionality.

PTE-2. Into a 500 mL four-neck, round bottom flask fitted with astirrer, thermometer, chilled water condenser and a pressure equalizingaddition funnel was added 206.54 grams of a 20% aqueous solution ofsodium hydroxide (1.033 moles). To this was added, drop wise withstirring, 94.08 grams (0.51 moles) DMDO, and the mixture then allowed tocool to approximately 21° C. 96.4 grams (1.065 moles) CMP was added dropwise with vigorous stirring, and stirring continued for another 2 hours.The mixture was then held at 21° C. for approximately 16 hours, afterwhich 150 grams of a clear layer was decanted. NMR analysis confirmedthe decanted layer to be CMP diene.

Into a 100-mL round bottom flask equipped with an air-driven stirrer,thermometer, and a dropping funnel, was added 39.64 grams (0.22 moles)DMDO and 4.10 grams (0.0125 moles) E-8220. To this mixture was added0.02 grams DABCO. The system was flushed with nitrogen, then mixed andheated for 1.5 hours at 60-70° C. 3.66 grams (0.0125 moles) CMP dienewas added followed by approximately 0.01 grams VAZO 52. With continuousstirring, the mixture was heated to 60° C., and held at this temperaturefor approximately 1.5 hrs. 0.83 grams (0.005 mole) TVCH were added andthe temperature maintained for another 1.5 hrs. 31.80 grams (0.157moles) DVE-3 were slowly added drop-wise to the flask over a period of45-60 minutes, keeping the temperature at approximately 70° C.Additional VAZO 52 was added in approximately 0.01 gram increments overapproximately 16 hours, for a total amount of about 0.4 grams. Thetemperature is raised to 100° C. and the material degassed forapproximately 10 minutes. The resultant polythioether was approximately3200 Mn with a 2.2 functionality.

Example 1

Part A was prepared by dissolving 0.0139 grams BPO and 0.0300 gramsI-819 in 3.0000 grams DVE-3 in a 20 mL amber vial, on a roll mill for 40minutes at 21° C. Part B was prepared by dissolving 0.0139 grams DHEPTand 0.0394 grams I-819 in 3.9407 grams TPTMP in a 20 mL amber vial, alsoon a roll mill for 8 hours at 21° C. Part A was then added to Part B andmanually stirred for one minute until homogeneously dispersed.

Examples 2-8

The procedure generally described in Example 1 for preparing homogeneousmixtures of peroxide, photo initiator and vinyl monomer in Part A, andamine, photo initiator and thiol monomer in Part B, was repeatedaccording to the formulations listed in Tables 1A and 1B.

Example 9

Part A was prepared by dissolving 0.0347 grams BPO and 0.1549 gramsI-819 in 15.0000 grams DVE-3 in a 20 mL amber vial, on a roll mill for40 minutes at 21° C. The solution was transferred to a speed mixer jar.0.1000 grams A-200 and 5.3111 grams clay were added to the solution andhomogeneously dispersed by means of a high speed mixer at 2,000 rpm forone minute. Part B was prepared by dissolving 0.0347 grams DIPEA and0.1974 grams I-819 in 19.7034 grams TPTMP in a 40 mL amber vial, also ona roll mill for 40 minutes at 21° C. The solution was transferred to aspeed mixer jar. 0.1000 grams A-200 and 1.8916 grams clay were added tothe solution and homogeneously dispersed by means of the high speedmixer at 2,000 rpm for one minute. Part A and Part B were homogeneouslydispersed through a static mixer.

Example 10

The procedure generally described in Example 9 for preparing homogeneousmixtures of Part A and Part B was repeated according to the formulationslisted in Tables 1A and 1B.

Example 11

The procedure generally described in Example 1 for preparing homogeneousmixtures of Part A and Part B was repeated according to the formulationslisted in Tables 1A and 1B.

Example 12

0.0694 grams I-819 was dissolved in a mixture of in 3.0000 grams DVE-3and 3.9407 grams TPTMP in a 20 mL amber vial, on a roll mill for 40minutes at 21° C.

Example 13

The procedure generally described in Example 1 for preparing homogeneousmixtures of Part A and Part B was repeated according to the formulationslisted in Tables 1A and 1B.

Example 14

0.0765 grams I-819 was dissolved in a mixture of in 4.0000 grams DMDOand 3.3467 grams TAC in a 20 mL amber vial, on a roll mill for 40minutes at 21° C.

Example 15

The procedure generally described in Example 1 for preparing homogeneousmixtures of Part A and Part B was repeated according to the formulationslisted in Tables 1A and 1B, wherein Part B was mixed for 24 hours ratherthan 8 hours.

Example 16

The procedure generally described in Example 1 for preparing homogeneousmixtures of Part A and Part B was repeated according to the formulationslisted in Tables 1A and 1B.

TABLE 1A Part A Composition (grams) Example BPO MEKP I-819 DVE-3 MEHQTEMPO TBPO TVBT 1 0.0139 0 0.0300 3.0000 0 0 0 0 2 0.0139 0 0.03003.0000 0.0018 0 0 0 3 0.0278 0 0.0300 3.0000 0 0.0009 0 0 4 0.0139 00.0300 3.0000 0 0 0 0 5 0.0070 0 0.0300 3.0000 0 0 0 0 6 0 0 0.03003.0000 0 0 0.0139 0 7 0.0171 0 0.0554 0 0 0 0 5.5359 8 0.0171 0 0.0554 00 0 0 5.5359 9 0.0347 0 0.1549 15.0000 0 0 0 0 10 0.0532 0 0.111611.5000 0 0 0 0 11 0.0139 0 0.0600 6.0000 0 0 0 0 12 0 0 0.0694 3.0000 00 0 0 13 0 0 0.0400 0 0 0 0 0 14 0 0 0.0765 0 0 0 0 0 15 0.0134 0 0.00350 0 0 0 0.3468 16 0 0.0230 0.0300 0.0624 0 0 0 0 Part A Composition(grams) Example A-200 DSW S-31 DIPEA DMDO TAC TMPTP 1 0 0 0 0 0 0 0 2 00 0 0 0 0 0 3 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 6 0 0 0 0 00 0 7 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 9 0.1000 5.3111 0 0 0 0 0 10  0.30000 2.9669 0 0 0 0 11  0 0 0 0 0 0 0 12  0 0 0 0 0 0 3.9407 13  0 0 00.0153 4.0000 0 0 14  0 0 0 0 4.0000 3.6467 0 15  0 0 0 0 0 0 0 16  0 00 0 0 0.1197 0

TABLE 1B Part B Composition (grams) Example DHEPT PMETA I-819 TPTMPDIPEA DMDO A-200 DSW S-31 BPO TAC PTE-1 PTE-2 1 0.0139 0 0.0394 3.9407 00 0 0 0 0 0 0 0 2 0.0139 0 0.0394 3.9407 0 0 0 0 0 0 0 0 0 3 0.0278 00.0394 3.9407 0 0 0 0 0 0 0 0 0 4 0 0 0.0394 3.9407 0/0139 0 0 0 0 0 0 00 5 0 0 0.0394 3.9407 0.0070 0 0 0 0 0 0 0 0 6 0 0 0.0394 3.9407 0.01390 0 0 0 0 0 0 0 7 0.0171 0 0.0300 0 0 3.0000 0 0 0 0 0 0 0 8 0 0 0.03000 0.0171 3.0000 0 0 0 0 0 0 0 9 0 0 0.1974 19.7034 0.0347 0 0.10001.8916 0 0 0 0 0 10 0 0 0.1516 15.1059 0.0532 0 0.3000 0 1.0631 0 0 0 011 0 0 0.0788 7.8814 0 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 0 0 0 0 0 13 00 0.0365 0 0 0 0 0 0 0.0153 3.6467 0 0 14 0 0 0 0 0 0 0 0 0 0 0 0 0 150.0134 0 0.0300 0 0 0 0 0 0 0 0 3.0000 0 16 0 0.0160 0.0300 0 0 0 0 0 00 0 0 3.0000

Evaluations

The following molds were used for curing evaluations:

Glass mold. An elongate 25 cm by 1.27 cm by 0.1 cm deep silicone rubbermold over a glass base, with an opaque silicone rubber sheet coveringall but 1.27 cm of one end of the mold.

Aluminum, frit glass and black coated wood molds. An elongate 10 cm by1.27 cm by 0.1 cm deep silicone rubber mold over an aluminum, frit glassor black coated wood base, with an opaque silicone rubber sheet coveringall but 1.27 cm of one end of the mold.

Teflon™ mold. A 8.4 cm by 3.2 cm by 0.2 cm deep silicone rubber moldover a Teflon™ base, with an opaque silicone rubber sheet covering allbut 2 cm of one end of the mold.

The curable composition was applied to the mold, an opaque siliconerubber sheet was then laid over the curable composition according to thedimensions described above.

The remaining exposed area of the composition was then exposed to a 88mW 455 nm LED light source, at a distance of 1.27 cm, for between 10-60seconds. The following thiol-ene curing evaluations are listed in Tables2 and 3.

TABLE 2 Cure Length (cm) After 60 second Exposure Example Mold FullyCured Partially Cured 5 Glass 4 cm 14 cm  11 Glass 3 cm 8 cm 12 Teflon7.6 cm   N/A Aluminum 2.2 cm   N/A Black frit 1.3 cm   N/A primed glassGlass 8 cm 13 cm  Black coated 4 cm 4 cm wood surface 13 Glass 4 cm 4.5cm   Black coated 1 cm 3 cm wood surface 14 Black coated <1 cm  1 cmwood surface

TABLE 3 Approximate Maximum Approximate Processing Time ApproximatePhoto Redox Cure Example (minutes) Cure Time (seconds) Time (minutes) 10 N/A* 0.25 2 0 N/A* 0.25 3 3 10 10 4 30 10 180-240 5 60 10 180-300 6120-240 10 720-960 7 0 N/A* 0.25 8 15 10 180-240 9 60 60 180-300 10 3060 180-240 15 0 N/A* 5 16 30 10 720-840 *N/A: The thiol-ene compositioncured during the mixing step and could not be applied to the mold.

The Tg of photo-initiated and redox-initiated Examples 1, 7, and 15 weremeasured using a model “DSC Q2000” differential scanning calorimeter,obtained from TA Instruments, New Castle, Del. Results are listed inTable 4.

TABLE 4 Tg (° C.) Redox Example Photo initiation initiation 1 −44° C.−46° C. to −41° C. 7 −44° C. −51° C. to −50° C. 15 −55° C. −55° C.

Various modifications and alterations of this disclosure will becomeapparent to those skilled in the art without departing from the scopeand principles of this disclosure, and it should be understood that thisdisclosure is not to be unduly limited to the illustrative embodimentsset forth hereinabove.

1. A composition that is curable to a polythioether polymer, comprising:a) a dithiol monomer; b) a diene monomer; c) a radical cleavedphotoinitiator; d) a peroxide; and e) an amine; where the peroxide andamine together are a peroxide-amine redox initiator.
 2. The compositionaccording to claim 1 where the amine is a tertiary amine.
 3. Thecomposition according to claim 1 where the amine is selected from thegroup consisting of dihydroxyethyl-p-toluidine,N,N-diisopropylethylamine, and N, N, N′, N″,N″-pentamethyl-diethylenetriamine.
 4. The composition according to claim1 where the peroxide is selected from the group consisting ofdi-tert-butyl peroxide, methyl ethyl ketone peroxide, and benzoylperoxide.
 5. The composition according to claim 1 additionallycomprising: f) a polythiol monomer having three or more thiol groups. 6.The composition according to claim 1 additionally comprising: g) atleast one filler.
 7. The composition according to claim 1 additionallycomprising: h) at least one nanoparticle filler.
 8. The compositionaccording to claim 1 additionally comprising: j) calcium carbonate. 9.The composition according to claim 1 additionally comprising: k)nanoparticle calcium carbonate.
 10. The composition according to claim 1which is curable by actinic light source.
 11. The composition accordingto claim 1 which is curable by blue light source.
 12. The compositionaccording to claim 1 which is curable by UV light source.
 13. A sealantcomprising the composition according to claim
 1. 14. A polythioetherpolymer obtained by cure of any the composition according to claim 1.15. The polythioether polymer according to claim 14 having a Tg lessthan −50° C.
 16. The composition according to claim 3 where the peroxideis selected from the group consisting of di-tert-butyl peroxide, methylethyl ketone peroxide, and benzoyl peroxide.
 17. The compositionaccording to claim 3 additionally comprising: k) nanoparticle calciumcarbonate.
 18. The composition according to claim 16 additionallycomprising: k) nanoparticle calcium carbonate.
 19. A polythioetherpolymer obtained by cure of the composition according to claim 16, thepolythioether polymer having a Tg less than −50° C.
 20. A polythioetherpolymer obtained by cure of the composition according to claim 18, thepolythioether polymer having a Tg less than −50° C.